Method for forming electric lamps and similar devices



July 30, 1968 H. SCHOR 3,395,007

METHOD FOR FORMING ELECTRIC LAMPS AND SIMILAR DEVICES Filed Aug. 2, 1965 INVEN TOR.

1! TTORNE l 3,395,007 Patented July 30, 1968 3,395,007 METHOD FOR FORMING ELECTRIC LAMPS AND SIMILAR DEVICES Herbert Schor, Brielle, N..l., assignor to Signalite Inc., Neptune, N.J., a corporation of New Jersey Filed Aug. 2, 1965, Ser. No. 476,274 4 Claims. (Cl. 65-34) ABSTRACT OF THE DISCLOSURE A method of fabricating an electrical lamp or similar device in which the exhaust tabulation is on the same end as the leads in which a coolant is passed through the tabulation while sealing in the leads to prevent collapse of the tabulation.

The present invention relates to electrical devices such as lamps and glow discharge devices and more particularly to a method for fabricating such devices.

Heretofore certain miniature type lamps and glow discharge devices have been fabricated by sealing the leadin wires which are connected to the electrodes in one end of a glass envelope and on the other end an exhaust tubulation which is provided for evacuation of the envelope and for the gas filling thereafter. After evacuation, the tabulation is then sealed and pinched off. This leaves a pointed tip on the end of the envelope which is objectionable, not only because of space limitations but also because of loss of end-on light from the device together with a poor appearance. Further it is desirable for some applications to have a flat or lens on the end of the envelope.

Attempts have been made to have the exhaust tubulation on the same end as the leads, however, due to the small size of the devices it has proven diflicult to seal in the lead-in wires without the heat necessary causing the tabulation to soften and become restricted. This makes it difficult to secure the proper evacuation and filling with gas of the device.

In the present invention the aforenoted difiiculty is overcome by passing a coolant, such, for example, as air through the tabulation while sealing in the leads, This prevents the restriction of the interior of the tabulation. After sealing in the leads, the open end is then sealed off and the device is ready for processing.

An object of the invention is to provide an improved glow discharge device.

Another object of the invention is to provide a novel method for fabricating a glow discharge device or the like.

Another object of the invention is to provide a novel method of fabricating a miniature lamp having the exhaust tip on the same end as the leads.

A further object of the invention is an improved method of making a miniature glow lamp in which the shape of the end may be as desired.

The above and other objects and features of the invention will be apparent to those skilled in the art from a consideration of the following description and drawings.

In the drawing:

FIGURE 1 is a diagrammatical view of a completed device made by the method of the invention.

FIGURES 2 to 8 are views illustrating the successive steps for making a device in accordance with the invention.

Referring now to the drawing, a glow lamp or discharge device of the miniature type such as may be made by the present invention is designated generally by the numeral 11. The device 11 has a glass envelope 12 formed at one end with a stem piece 13 which includes a tipoff 14. Lead-in wires 15 extend through the press 13 and are sealed to form a vacuum tight seal therewith. Connected to the leads 15 are electrodes 16 which may be of a suitable electrode material such, for example, as nickel wire. The envelope 12 contains a filling of gas, such, for example, as neon, argon, or a mixture thereof. In the fabrication of the device 11, the envelope 12 is exhausted and the gas filling introduced through a tubulation 17 extending from the press 13. After the gas filling, the tabulation 17 is then tipped off to form the tipoff 14.

Reference is now made to FIGURES 2 to 8 of the drawing to illustrate the method of manufacturing the device 11, illustrated in FIGURE 1. In FIGURE 2 a glass tube 20 of a predetermined size is positioned to receive lead-in wires 15 and electrodes 16 therein. A second glass tube 21 of a smaller size than the tube 20 is positioned to extend just inside the tube 20. It is understood that the glass tubes 20, 21, and lead-in wires 15 may be positioned in apparatus of the general type conventionally employed in the manufacture of such type glow lamps. Such equipment has been omitted for the sake of simplicity as it is well known to those skilled in the art. A flame 23 is directed on the end of the tube 20 where it is heated to a plastic state.

With continued heating, see FIGURES 3, the end of the tube 20 is formed to contact the tube 21. At the same time a cooling fluid, indicated by the arrow 24, is passed through the tube 21 to prevent the interior thereof from becoming plastic and collapsing. The cooling fluid may be air, an inert gas or other suitable coolants. Next the leads 15 are sealed in and the tube 20 sealed to the tube 21 with the cooling fluid flowing through the interior of the tube 21, see FIGURE 4. The flow of coolant through the tube 21 is maintained to prevent the interior of the tube 21 from flowing to close up yet not to prevent the tube 20 from sealing with the tube 21 to make a vacuum tight joint therein.

After the tubes 20 and 21 are sealed together to form a unitary structure, a flame 25 is directed on the other end of the tube 20, see FIGURE 5, and heat applied until the glass becomes plastic. While in the plastic state the end of the tube 20 is shaped or molded to form closed end 26 of the envelope 11 such as is illustrated in FIG- URES 6 and 7. It is understood that the end 26 could be of other configurations than those illustrated. In the example illustrated the end 26 is formed after the leads 15 are sealed in, it is understood that it could be formed first.

The device 11 is then exhausted, filled with a suitable gas and tipped off as shown in FIGURE 8 to complete the envelope 12 by the method disclosed herein. It is understood that the method can be carried out by utilizing conventional machinery employed in the manufacture of miniature type glow lamps or discharge devices.

Other means can be provided for the prevention of the tabulation from restricting when heated to a plastic state, As an example, a rod of stainless steel or a similar material could be inserted in the tabulation to prevent restriction when in a plastic state.

Thus the present invention provides a method for fabricating a miniature type glow lamp in which the tubulation and lead-in wires are at the same end. This eliminates the tip from the other end which is objectionable for a number of reasons. One of these reasons is that the tip which was on the light end would interfere with the light passing through and also present a very poor appearance. Another feature is that the method set forth permits a smaller overall size without shortening the electrodes.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention.

What is claimed is:

1. The method of making an electric lamp or similar device comprising the steps of positioning lead-in wires having electrodes on one end thereof so that the electrodes extend into one end of a glass tube, placing a small er glass tube into the said end of said first gas tube to position said lead-in wires between said glass tubes, pass ing a flow of coolant through said smaller glass tube and applying heat to seal the said end of said first glass tube to said smaller glass tube thereby scaling in said leadin wires, removing said flow of coolant, heating the other end of said first glass tube and forming to close the end to make a bulb-like structure, evacuating through said smaller glass tube, filling with gas through said smaller glass tube, and tipping off said smaller glass tube and sealing.

2. The method of making a tubulated envelope assembly for an electric lamp or similar device, said method comprising the steps of placing electrodes into a glass cylinder with lead-in wires attached to the electrodes extending from said glass cylinder, placing a glass tubulation in the end of said glass cylinder adjacent to said leadin wires, passing a flow of coolant through said tubulation while heating said glass cylinder and said tubulation to a plastic state, continuing heating and forming a seal between said glass cylinder and said tubulation with the lead-in wires sealed therewith, heating the other end of said glass cylinder to a plastic state and forming an end seal thereon.

3. A method of forming electric lamps or similar devices comprising the steps of placing a plurality of electrodes into one end of a glass cylinder with lead-in wires from said electrodes extending out of said end, placing a glass tubulation adjacent to said end of said glass cylinder, passing a flow of coolant through said tubulation, heating the said end of said glass cylinder and the outer surface of said tubulation to a plastic state, forming said end of said glass cylinder to make a seal with said tubulation and to seal said lead-in wires in said seal, heating the other end of said glass cylinder to a plastic state and forming said other end of said glass cylinder to enclose the end thereof, and tipping off said tubulation.

4. A method of forming electric lamps or similar devices comprising the steps of placing a plurality of electrodes into one end of a glass tube with lead-in Wires from said electrodes extending out of said end, placing a glass tubulation adjacent to said end of said glass cylinder, heating the end of said glass tube and said tubulation to a plastic state while providing means for preventing the restriction of said tubulation, forming said end of said glass tube to make a seal with said tubulation and to seal in said lead-in wires, heating the other end of said glass tube to a plastic state and forming said other end of said glass tube to seal the end thereof, and tipping off said tubulation.

References Cited UNITED STATES PATENTS 2,159,736 5/1939 Geiger et al 65 2,413,338 12/1946 Small 65-36 3,078,694 2/1963 Schoenmakers et a1. 65270 X 3,270,237 8/1966 Danko 65138 X DONALL H. SYLVESTER, Primary Examiner.

R. LINDSAY, Assistant Examiner. 

